CLASSIFICATION OF BACTERIA NODULATING LATHYRUS-JAPONICUS AND LATHYRUS-PRATENSIS IN NORTHERN QUEBEC AS STRAINS OF RHIZOBIUM-LEGUMINOSARUM BIOVAR VICIAE

The diversity of two populations of rhizobia isolated from Lathyrus ja ponicus (30 strains) and Lathyrus pratensis (49 strains) growing in no rthern regions of Quebec, Canada, was determined on the basis of pheno typic characteristics, multilocus enzyme electrophoresis, DNA-DNA homo logy, and 16S ribosomal DNA sequencing, According to numerical analysi s of phenotypic characteristics, strains were divided into four groups , Strains isolated from L. pratensis fell in groups I to III; the latt er included reference strains of Rhizobium leguminosarum, All strains isolated from L. japonicus were included in group N. All strains had n odulation characteristics similar to those of R. leguminosarum by. vic iae. Strains isolated from L. japonicus originating from an arctic reg ion were usually able to grow at 5 degrees C and were more likely to b e tolerant to copper (CuCl2 . H2O, 100 mu g/ml) acid lead [Pb(CH3COO)( 2), 500 mu g/ml] than strains isolated from L. pratensis from a boreal zone, However, both populations of Lathyrus strains were adapted to t he cold in comparison to reference strains from temperate regions, Eac h population had similar genetic diversity (H = 0.45), determined by m ultilocus enzyme electrophoresis of the loci encoding eight enzymes, b ut the diversity obtained by analyzing all strains including the refer ence strains (H = 0.58),vas higher, Representative strains of both pop ulations shelved high levels of DNA homology among themselves and with R. leguminosarum. Partial sequences of the 16S ribosomal RNA genes we re similar to those reported for R. leguminosarum by. viciae. We concl ude that the strains isolated from L. japonicus and L. pratensis belon g to R. leguminosarum by, viciae but are distinguishable by growth at 5 degrees C, which is a characteristic related to their geographic ori gin.